Constraints on CP-violating gauge-Higgs operators

TL;DR

This paper investigates the constraints on CP-violating gauge-Higgs operators of dimension six using electroweak precision data, Higgs measurements, and electric dipole moments, highlighting the strongest bounds from EDMs.

Contribution

It provides a comprehensive analysis of CP-violating operators' effects on Higgs and gauge interactions, combining multiple experimental constraints to limit new physics.

Findings

Electric dipole moments impose the strongest constraints.

Electroweak precision data provide the weakest bounds.

Diphoton Higgs signal strength offers significant constraints.

Abstract

We consider the most general set of $SU(2) \times U(1)$ invariant CP-violating operators of dimension six, which contribute to $VVh$ interactions ($V = W, Z, \gamma$). Our aim is to constrain any CP-violating new physics above the electroweak scale via the effective couplings that arise when such physics is integrated out. For this purpose, we use, in turn, electroweak precision data, global fits of Higgs data at the Large Hadron Collider and the electric dipole moments of the neutron and the electron. We thus impose constraints mainly on two-parameter and three-parameter spaces. We find that the constraints from the electroweak precision data are the weakest. Among the existing Higgs search channels, considerable constraints come from the diphoton signal strength. We note that potential contribution to $h \rightarrow \gamma Z$ may in principle be a useful constraining factor, but it can be utilized only in the high energy run. The contributions to electric dipole moments mostly lead to the strongest constraints, though somewhat fine-tuned combinations of more than one parameter with large magnitudes are allowed. We also discuss constraints on gauge boson trilinear couplings which depend on the parameters of the CP-violating operators .